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Pandiyan B.,University of Wisconsin - Whitewater | Merrill S.J.,Marquette University | Benvenga S.,Policlinico Universitario Of Messina
Mathematical Medicine and Biology | Year: 2014

The purpose of modelling the negative-feedback control mechanism of the hypothalamus-pituitary- thyroid (HPT) axis in autoimmune (Hashimoto's) thyroiditis is to describe the clinical course of euthyroidism, subclinical hypothyroidism and overt hypothyroidism for patients. Thyroid hormone thyroxine (T4) and triiodothyronine (T3) levels are controlled by negative-feedback control through thyroidstimulating hormone (TSH). T4, like other hormones, can be bound or unbound; the unbound T4 (FT4) is used as a marker for hypothyroidism. Autoimmune thyroiditis is a disease in which the thyroid-infiltrating lymphocytes attack autoantigens in follicle cells, destroying them over a long time. To describe the operation of the feedback control, we developed a mathematical model involving four clinical variables: TSH, FT4, anti-thyroid peroxidase antibodies and the thyroid gland's functional size. The first three variables are regularly measured while the last variable is determined through relationships between the other three variables. The problem of two different time scales for circulating hormones and thyroid damage is addressed using singular perturbation theory. Analysis of the mathematical model establishes stability and conditions under which the diseased state can maintain the slow movement toward diseased state equilibrium. Although we have used four variables in modelling the feedback control through the HPT axis, the predicted clinical course given any set of parameters is shown to depend on the steady-state levels of TSH and FT4. This observation makes possible the development of the clinical charts based only on the levels of TSH, time and potential steady-state values. To validate the model predictions, a dataset obtained from a Sicilian adult population has been employed. © The authors 2013. Source

Costa S.,Policlinico Universitario Of Messina
Quaderni ACP | Year: 2012

A necrotic lesion of the scalp leads to a not frequent diagnosis: the TIck BOrne LymphAdenitis (TIBOLA) caused by a tick diffused in Sicily. Source

Ehrenkranz J.,Intermountain Central Laboratory | Ehrenkranz J.,Intermountain Medical Center | Bach P.R.,Central Laboratory | Snow G.L.,Statistical Data Center | And 5 more authors.
Thyroid | Year: 2015

Background: Establishing the reference interval for thyrotropin (TSH) and free thyroxine (T4) is clinically important because a number of disease states have been linked to alterations in TSH and free T4 concentrations that are within the 95% confidence interval for normal thyroid hormone values. Age, sex, time of day, and ethnicity are known to affect circulating levels of TSH and free T4 but have not been used to establish reference intervals. The purpose of this study was to define the reference interval for TSH and free T4 taking into account age, sex, ethnicity, and circadian and circannual variability. Methods: We performed a retrospective analysis of 465,593 TSH and 112,994 free T4 measurements from subjects ages 1-104 years with no thyroid disease using a single TSH and free T4 immunoassay method. Boundaries for the central 95% of patient values, taking into account hour of day, day of year, sex, and age were calculated. Results: Females had significantly higher TSH and free T4 levels than males; the magnitude of these differences did not exceed 0.1 mIU/L or 0.1 ng/dL respectively. Although the 2.5% TSH reference interval remains constant through the day, date, and age ranges, the upper limit (97.5%) of the TSH reference interval increases from 6.45 to 7.55 mIU/L with age, due primarily to a progressive increase in the amplitude of the nocturnal TSH surge. Additionally, significant ethnic differences in TSH circadian periodicity occur between African American, Pacific Island, and Caucasian populations. Conclusions: The reference interval for TSH varies significantly by age, sex, hour of day, and ethnicity. Time of year does not affect the TSH reference interval, and age, sex, hour of day and time of year do not affect the free T4 reference interval. © Copyright 2015, Mary Ann Liebert, Inc. Source

Costa S.,Policlinico Universitario Of Messina | Nibali R.C.,Scuola di Specializzazione in Pediatria
Quaderni ACP | Year: 2012

Acute Otitis Media (AOM) is among the leading causes of use of antibiotics in childhood. The majority of episodes of AOM tends to resolve spontaneously; for this reason the wait and see strategy before starting antibiotics is a long established practice, which allows significant sparing in drugs. In January 2011 two RCTs were published in the NEJM about the early use of amoxicillin-clavulanate in the treatment of AOM; conclusions indicated an advantage in the early use of antibiotics. In this article we evaluate the methods and conclusions of the two RCTs. We believe that the applicability to current practice is distorted by the selection of patients with more severe disease, the use of instrumental ascertained outcomes that are not easily applicable, the difficulty of interpretation due to the complex or multiple outcomes considered; actually the efficacy of antibiotics does not appear greater than that reported in previous studies. We show that the NNH is comparable to the NNT. Source

Palmery M.,University of Rome La Sapienza | Palmery M.,Pharma Srl | Saraceno A.,University of Rome La Sapienza | Saraceno A.,Pharma Srl | And 4 more authors.
European Review for Medical and Pharmacological Sciences | Year: 2013

Oral contraceptives (OCs) are a major class of prescription drug, used by a large proportion of women starting from early adolescence. Much research has been conducted to investigate the physiological changes that occur in women who take OCs. These include changes in general health as well as in nutritional needs. In terms of nutrition, several studies investigated whether women on OCs need different amounts of some vitamins and minerals. In particular, a report from theWorld Health Organization (WHO) points out that the influence of OCs on nutrient requirements is a topic of high clinical relevance and should, therefore, receive great attention. It has been shown that the key nutrient depletions concern folic acid, vitamins B2, B6, B12, vitamin C and E and the minerals magnesium, selenium and zinc. Most research has focused on the levels of these vitamins and minerals in the blood of women who take OCs compared to women who do not. Since women who take OCs not always have adequate diet, may have unhealthy life style or may suffer from pathologies of malabsorption, the possibility to prevent vitamin and mineral deficiencies by taking appropriate dietary supplements should be considered a first-line approach by clinicians. Source

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